Conventionally, a strut mount as shown in the following patent document 1 (PTL1) is known, for example. This conventional strut mount comprises an inside clasp attached to a piston rod and an outside clasp connected with the inside clasp through an elastic member. Here, the elastic member used for this conventional strut mount consists of a first rubber and a second rubber with a dynamic multiplication, which is a ratio of a spring constant under a dynamic load to a spring constant under a static load, and a damping characteristic tan 6 larger than those of the first rubber. The first rubber and the second rubber are integrally attached at least to the inside clasp, and the first rubber is configured to contact with the faceplate portion of the outside clasp under an overall range of load including no load, and the second rubber is configured to contact with the faceplate portion of the outside clasp only under a load exceeding a predetermined value.
Moreover, conventionally, a strut mount as shown in the following patent document 2 (PTL2) is also known. This conventional strut mount comprises an inner cylinder fixed at the end of a piston rod of a shock absorber, a vibration-isolation substrate consisting of a rubber-like elastic object disposed in this inner cylinder and a pair of upper and lower brackets which forms a housing portion for containing this vibration-isolation substrate and is fixed to the vehicle body side by a plurality of mounting members.
Moreover, conventionally, a strut mount as shown in the following patent document 3 (PTL3) is also known, for example. This conventional strut mount comprises an outer member, an inner mounting member and an elastic object, and the elastic object consists of a rubber elastic portion and a low-density portion. This rubber elastic portion is cure-adhered to the inner mounting member, and its upper surface and lower surface are formed in a shape of a wave which has amplitude in an axial direction of the strut mount. The low-density portion is formed of an expandable urethane and a soft rubber, etc., for example.
Furthermore, conventionally, a strut mount as shown in the following patent document 4 (PTL4) is also known, for example. This conventional strut mount comprises an outside clasp attached to a vehicle body, an inside clasp attached to a piston rod of a shock absorber, and a rubber elastic object interposed between the outside clasp and the inside clasp by being pressed into a housing portion of the outside clasp in a status that it is formed integrally with the inside clasp at the outer periphery of the inside clasp. This conventional strut mount is configured so that a soft layer (urethane) with a higher loss coefficient and a lower density than those of the rubber elastic object is interposed between the outside clasp and the rubber elastic object and thereby the soft layer absorbs a minute high-frequency oscillation and the rubber elastic object absorbs a big external force.